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  <title>判断是否为无限值</title>

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   <div class="refnamediv">
    <h1 class="refname">is_infinite</h1>
    <p class="verinfo">(PHP 4 &gt;= 4.2.0, PHP 5)</p><p class="refpurpose"><span class="refname">is_infinite</span> &mdash; <span class="dc-title">判断是否为无限值</span></p>

   </div>
 <div class="refsect1 description" id="refsect1-function.is-infinite-description">
  <h3 class="title">说明</h3>
   <div class="methodsynopsis dc-description">
    <span class="type">bool</span> <span class="methodname"><strong>is_infinite</strong></span>
     ( <span class="methodparam"><span class="type">float</span> <code class="parameter">$val</code></span>
    )</div>

    <p class="para rdfs-comment">
     如果 <em><code class="parameter">val</code></em>
     为无穷大（正的或负的），例如 <em>log(0)</em>
     的结果或者任何超出本平台的浮点数范围的值，则返回 <strong><code>TRUE</code></strong>。
    </p>
   </div>

    <div class="refsect1 parameters" id="refsect1-function.is-infinite-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<em><code class="parameter">val</code></em></dt>

     <dd>

      <p class="para">
       要检查的值
      </p>
     </dd>

    
   </dl>

  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-function.is-infinite-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   如果 <em><code class="parameter">val</code></em>
     为无穷大返回 <strong><code>TRUE</code></strong>，否则返回 <strong><code>FALSE</code></strong>。
  </p>
 </div>

 <div class="refsect1 seealso" id="refsect1-function.is-infinite-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="function.is-finite.html" class="function" rel="rdfs-seeAlso">is_finite()</a> - 判断是否为有限值</span></li>
    <li class="member"><span class="function"><a href="function.is-nan.html" class="function" rel="rdfs-seeAlso">is_nan()</a> - 判断是否为合法数值</span></li>
   </ul>
  </p>
 </div>

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